A photoelectrochemical sensor for highly sensitive detection of amyloid beta based on sensitization of Mn:CdSe to Bi2WO6/CdS.

Abstract A high sensitivity photoelectrochemical (PEC) immunosensor for amyloid beta (Aβ) detection, which has great neurotoxic effect on the progression of Alzheimer's disease (AD), was presented based on the sensitization of Mn2+ doped CdSe (Mn:CdSe) to Bi 2 WO 6 /CdS electrode. Bi 2 WO 6 was synthesized successfully with a unique flower-like amorphous structure, providing a merit to load functional CdS for obtaining an expected PEC response. Mn:CdSe was used to label Aβ for acquiring Mn:CdSe-Aβ bioconjugate and enhancing the detection sensitivity via the competitive immunoreaction of Mn:CdSe-Aβ and Aβ with antibody immobilized on Bi 2 WO 6 /CdS electrode. The doped of Mn2+ in CdSe nanoparticles could induce energy defect that impeded the recombination of photo-generated charges, and greatly enhanced PEC response for ultrasensitive detection of Aβ. The proposed immunosensor for Aβ showed a linear range of 0.2 pg mL−1–50 ng mL−1 with a detection limit of 0.068 pg mL−1, also with good stability, high selectivity, and acceptable reproducibility. The sensitization of Mn:CdSe provided a new way for preparation of highly sensitive protein biosensors. Highlights • A novel PEC immunosensor for ultrasensitive detection of Aβ was proposed at Bi 2 WO 6 /CdS modified electrode. • Aβ was labeled with Mn2+ doped CdSe for signal amplification. • The sensitization of Mn:CdSe to Bi 2 WO 6 /CdS remarkably enhanced the PEC intensity. • The biosensor for Aβ exhibited the detection limit of 0.068 pg mL−1. [ABSTRACT FROM AUTHOR]